One of the problems with metal beverage cans, since they are used in great numbers, is that once empty they create great volumes of trash. Although many people know that it is advisable to recycle aluminum cans, the usual excuse for not going so is that the empty cans take up too much room. To reduce this bulk, many types of mechanical can crushers have been developed. Although can crushers may work, they are not an ideal solution for many people. Can crushers become one more thing cluttering up the house, their existence based upon the often weak desire of the owner to make big cans into little cans.
Recognizing this, several systems have been developed to allow people to crush beverage cans by hand. See for example, U.S. Pat. Nos. 3,850,338 and 3,918,603 to Hatada and 4,322,013 to Tanaka and PCT Application WO 83/02602. These references all disclose the use of grooves or creases in the can, along what can be considered fold lines, to allow the cans to be crushed by hand.